Antiskinning compound and compositions containing them

ABSTRACT

The invention relates to anti-skinning agents containing combinations of (a) organic or inorganic oxygen scavengers with (b) alkylamines and/or alkyl alkanolamines and also relates to compositions containing the combination, especially oxidatively drying paints or coating compositions and articles coated with such oxidatively drying paints or coating compositions.

This application is a continuation in part of U.S. application Ser. No.10/859,304, filed Jun. 2, 2004.

FIELD OF THE INVENTION

The invention relates to anti-skinning agents containing mixtures ofcompounds (combinations of additives), coating compositions containingthem and articles coated with them. The compounds are selected from thegroups of (a) organic and inorganic oxygen scavengers with (b) aminesincluding alkyl amines and/or alkyl alkanolamines. The invention furtherrelates to compositions containing these anti-skinning agents, likecoating compositions such as oxidatively drying alkyd resins.

BACKGROUND OF THE INVENTION

Colorless and pigmented oxidatively drying paints and coatings based onoxidatively drying oils, alkyd resins, epoxy esters and otheroxidatively drying refined oils are known. These oils and binderscrosslink oxidatively under the influence of oxygen (preferablyatmospheric oxygen) by means of the addition of driers, such as metalcarboxylates of transition metals. If this crosslinking takes placebefore the product is actually used, they can form a solid barrier film,a skin, on the surface when stored in open or closed containers. This ishighly undesirable and should therefore be avoided since it makes thepaint more difficult to work with, and commonly interferes with theuniform distribution of the driers. The accumulation of the driers inthe paint skin that forms can lead to considerable delays in the dryingof the paint when it is applied.

Skinning of the paint film after application is also disadvantageous.Excessively rapid drying of the surface of the paint prevents the lowerfilm layers from drying evenly because they are shielded from oxygen,which is prevented from sufficiently penetrating into and dispersingwithin the paint film. This can lead among other things to flow problemsin the paint film, adhesion problems, or insufficiently hard films.

It is known to add organic substances to a paint that inhibit thereaction of the drier metal with (atmospheric) oxygen by binding theoxygen or by complexing of the drier metal.

U.S. Pat. No. 4,618,371 describes the use of aliphatic α-hydroxy ketonesas anti-skinning agents. DE-A 1 519 103. discloses N,N-dialkylatedhydroxylamines for this purpose. Because of their low volatility,however, hydroxylamines alone can lead to severe delays in drying andoften also to reduced film hardness values, so that their possibleapplications are limited. They have not been able to gain commercialacceptance as anti-skinning agents. U.S. patent application publicationNo. 2003/0025105 describes the use of organic hydroxylamines such asdiethylhydroxylamine and β-dicarbonyl compounds such as diethylformamideas anti-skinning agents.

A central issue in alkyd resin technology is to quickly cure the resinwhich occurs via oxidative crosslinking, while maintaining adequateanti-skinning properties. Anitskinning requires slowing the curingreaction at the air-resin interface. Oximes, which act as oxygenscavengers, or suitable phenolic compounds are most often used today asanti-skinning agents in industry. However, the phenolic anti-skinningagents display a significant delay in surface drying such that alonethey are only suitable for certain coating compositions. Oximes such ase.g. methyl ethyl ketoxime (MEKO) or butyraldoxime, on the other hand,display only slight delays in surface drying due to their volatility.However, the high volatility of oximes results in rapid loss of thisanti-skin agent from the alkyd and thus does not adequately controlskinning. The most significant disadvantage of the oximes, which arewidely used today, lies in their toxicity. As a consequence of this,users have to observe elaborate personal protection precautions whenworking with paints containing oximes as anti-skinning agents.

It was discovered that the use of the combination of an antiskinningagent and a co-promoter as described below provides for inhibition ofskinning with minimal impact on drying properties. In particular, theabove-mentioned disadvantages of the specified hydroxylamines asanti-skinning agents could also be avoided by combining such substanceswith the additional compounds described below, and hence products thatbetter satisfy requirements as anti-skinning agents are obtained.

Incorporating the combinations according to the present invention intoan air-drying alkyd resin provides an alkyd resin system which isresistant to undesirable skinning and exhibits improved drying of theresin films after application.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to an anti-skinning agent containing

a) an organic or inorganic oxygen scavenger,with either or both of

b) an organic alkyl amine compound of formula II

where R³, R⁴ and R⁵ may be mutually independently hydrogen but all threecan not be hydrogen, a linear or branched, saturated or unsaturatedC₁-C₂₀ aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, or a C₆-C₁₂ aryl molecule or radical, a C₇-C₁₄araliphatic molecule or radical or a C₅-C₇ cycloaliphatic molecule orradical, and

c) an organic alkyl alkanolamine compound of formula (III)

where R⁶ and R⁸ may be mutually independently hydrogen but both can notbe hydrogen, a linear or branched, saturated or unsaturated C₁-C₂₀aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, a C₆-C₁₂ aryl radical, a C₇-C₁₄ araliphatic molecule orradical or a C₅-C₇ cycloaliphatic molecule or radical and R⁷ may be alinear or branched, saturated or unsaturated C₁-C₂₀ aliphatic moleculeor radical, which can optionally be mono- or polysubstituted, a C₆-C₁₂aryl molecule or radical, a C₇-C₁₄ araliphatic molecule or radical or aC₅-C₇ cycloaliphatic molecule or radical.

An organic or inorganic oxygen scavenger is a material which exhibitsthe ability to complex with free oxygen and slow its oxidativereactions. Representative examples of organic oxygen scavengers includebut are not limited to: hydroquinone, substituted hydroquinones,semi-hydroquinone, catechol, substituted catechols, erythorbic acid,hydroxylamine compounds, carbohydrazides and methyl ethyl ketoxime.Representative examples of inorganic oxygen scavengers include but arenot limited to sulfites.

Hydroxylamine oxygen scavengers in accordance with the present inventionare of the general formula:

where R¹ and R² mutually independently hydrogen, a linear or branched,saturated or unsaturated C₁-C₂₀ aliphatic molecule or radical, which canoptionally be mono- or polysubstituted, or a C₆-C₁₂ aryl molecule orradical, a C₇-C₁₄ araliphatic molecule or radical or a C₅-C₇cycloaliphatic.

Representative hydroxylamines include but are not limited to:hydroxylamine, methylhydroxylamine, dimethylhydroxylamine,methyl-ethylhydroxylamine, ethylhydroxylamine, diethylhydroxylamine,dibutylhydroxylamine, dibenzylhydroxylamine,mono-isopropylhydroxylarnine and mixtures thereof.

Hydroquinone oxygen scavengers in accordance with the present inventionmay be unsubstituted or substituted. The substituted hydroquinone oxygenscavengers can be substituted in the ortho or meta positions or bothwith moieties including but not limited to C-1 to C6 alkyl or arylmoieties. Representative examples of substituted hydroquinones includebut are not limited to methyl hydroquinone.

Representative organic alkyl amines include but are not limited to:monoethyl amine, diethyl amine, triethyl amine, monoisopropyl amine,diisopropyl amine, monobutyl amine, dibutylamine, tributyl amine,monoamyl amine, dimethyl ethyl amine, dimethyl isopropyl amine, ethyldiisopropyl amine, sec-butyl amine, tetramethylpropylenediamine,diethylaminopropylamine, 3-methoxypropylamine,dimethylaminopropylaminopropylamine and 3-isopropoxypropylamine andmixtures thereof.

Representative organic alkyl alkanolamines include but are not limitedto: methylaminoethanol, dimethylaminoethanol, methydiethanolamine,ethylaminoethanol, diethylaminoethanol, dimethylamino-2-propanol,isopropylaminoethanol, disiopropylaminoethanol, butylaminoethanol,dibutylaminoethanol, butyldiethanolamine, tert-butylaminoethanol andmixtures thereof.

The invention also relates to compositions of matter containing theseanti-skinning agents.

For the purposes of the invention mixtures of one or more organic orinorganic oxygen scavengers and either or both an organic alkyl amineand/or an organic alkyl alkanolamine compound are used alone or assolutions or dispersions or emulsions in water and/or organic solvents.Suitable organic solvents include all conventional solvents, such asaromatics, white spirits, ketones, alcohols, ethers and fatty acidesters. The present invention provides for a novel means of balancingthe need for a rapid dry through of an alkyd resin coating whilemaintaining an acceptable oxidative control at the air-resin interfaceto control skinning.

For the use according to the present invention the one or more organicor inorganic oxygen scavengers (A) and either or both an organic alkylamine (B) and/or an organic alkyl alkanolamine (C) can be used in abroad range of mixtures with one another. They are preferably used inthe ratio (A):(B) and/or (C)=from 0.01:75 to 75:0.01, preferably from0.05:30 to 30:0.05 and most preferably from 0.1:10 to 10:0.1 parts. In amixture consisting of all three components, each of the components canmutually independently preferably be used in the ratio 0.1 to 10 to eachof the other components used. They can be used in pure form or inaqueous solution or aqueous dispersion or emulsion or in the form ofsolutions in organic solvents. Aqueous in this context is intended tomean that water is either the sole solvent or is added in a quantity ofover 50 wt. % relative to the solvent blend together with conventionalorganic solvents (e.g. alcohols).

The amount of anti-skinning agent combination used in a coating systemprimarily depends on the content of binder and drier used in theparticular coating composition. As a general rule between 0.001 and 2.0wt. % of mixtures of compounds according to the present invention shouldbe added. Preferred amounts to be used are 0.01 to 0.5 wt. %, relativein each case to the overall composition of the coating composition. Theamounts can also depend on the type of binder and the pigments used inthe coating composition. Thus, in special systems the relative amount ofadditive to be used can also be greater than 2.0 wt. % (relative to theoverall composition).

It is an advantage of the anti-skinning agent combination of the presentinvention that it reliably prevents skinning in a wide range of bindersand when used with various driers but that it does not unfavorablyinfluence other drying properties of the resin.

The invention is further illustrated but is not intended to be limitedby the following examples in which all parts and percentages are byweight unless otherwise specified.

EXAMPLES

In examples 1 through 6 a common short oil resin, Beckosol 12054(available from Reichhold Chemicals, Inc.), containing 50% solids wasused. In examples 7 through 12, tung oil was used as the curing medium,with cobalt II added as a drying agent. When cobalt II is added to tungoil, it quickly causes curing and the formation of a hard surface film.

Example 1

This example shows the performance of a hydroxylamine,diethylhydroxylamine (DEHA)-amine formulations containing no additionalvolatile organic compounds such as diethyl formamide (DEF) in a shortoil alkyd resin (Beckosol 12054). MEKO (methyl ethyl ketoxime) wascompared to combinations of DEHA and alkyl amines or alklylalkanolamines. Cobalt octoate was added to the resin so the final cobaltion concentration was 0.2%. To the resin-cobalt mixture was added MEKO(available as a 25% active solution), DEHA with diethyl formamide (DEF),as a 14% active solution or DEHA with either alkyl amines or alkylalkanolamines. The samples were prepared on an eqi-molar basis using 750ppm of DEHA (e.g., 750 mg/l; 0.0084 mol DEHA/l). Ten-gram samples wereplaced in bottles and a small hole was drilled into the cap so air couldenter into the bottles. Air was swept over the top of the bottles usinga flow rate of about 100 feet per minute. The onset of skinning wasmonitored daily with the following results: TABLE 1 DiethylhydroxylamineDiethylhydroxylamine Diethylhydroxylamine MEKO MEKO (0.065 mmol) +Diethyl Diethylhydroxylamine (0.069 mmol) + (0.066 mmol) + Dibutyl(0.055 mmol (0.114 mmol formamide (0.068 mmol) + DiisoproplyaminoethanolEthylaminoethanol amine active) active) (0.016 mmol) (0.018 mmol) (0.018mmol) (0.016 mmol) 13 Days 20 Days 62 Days >70 Days >70 Days >70 Days

The MEKO samples showed poor resistance to skinning even at 0.114 mmolconcentration. The sample containing diethylhydroxylamine with theco-solvent diethyl formamide showed better anti-skinning performancethan MEKO. The samples containing diethylhydroxylamine with either analkyl amine or alkyl alkanolamine showed the overall best anti-skinningperformance. The surfaces of the last three samples were only tacky andnot completely skinned even after 70 days of exposure to air.

Similar skinning results were found with other combination ofdiethylhydroxylamine and other alkyl amines such as diisopropyl amine(DiPA), tributyl amine (TBA) and triethyl amine (TEA), all samples weretacky and not completely skinned after 70 days. Similarly, combinationsof diethylhydroxylamine with other alkyl alkanolamines such asdibutylaminoethanol (DBAE) also delayed skinning to greater than 70days. In all cases, the total concentration of DEHA with either thealkyl amine or the alkyl alkanolamines was about 0.081 mmol in theten-gram sample or about 8 mmol/kg of resin.

Example 2

This example shows the dry-through performance of the short-oil resinused in Example 1 with eqimolar amounts of prior art antiskinningagents, and those of the present invention based on 750 ppm DEHA (0.084mmol DEHA/10 gram of resin). The cobalt concentration for thisdry-through performance study was decreased to 0.1%. The combinations ofresin with the cobalt drier and the antiskinning agents were placed ontoa substrate and a drawdown bar was used to apply a three mil thickcoating. The samples were placed in an exhaust hood with air flowingover the samples at about 100 feet per minute. The tack-free time wasdetermined by the absence of a fingerprint on the resin.

The dry-through performance was monitored using a methyl ethyl ketone(MEK) double-rub. Cheesecloth was soaked in MEK for about ten secondsthen applied to the resin using a downward force of one pound per squarein (1 psi). One complete rub was counted as a forward and backwardstroke. The number of double-rubs necessary to remove the resin is anindication of the dry-through: the higher the number of MEK double rubs(DR), the faster the dry-through. Table 2 summarizes the results. TABLE2 MEKO (0.337 mmol) Borcher 0241 (0.337 mmol × 25% = (0.588 mmol) DEHA(0.068 DEHA (0.068 0.084 mmol (0.588 mmol × 14% = DEHA Only mmol) + DBAEmmol) + EAE DEHA (0.068 mmol) + DiPAE active 0.082 mmol Drying Time(0.086 mmol) (0.017 mmol) (0.017 mmol) (0.017 mmol) MEKO) activematerial) 1 3 4 5 6 7 8 Tack Free Tack Free Tack Free Tack Free TackFree Time < 3 mins Tack Free Time < Tack Free Time < 3 mins Time < 3mins Time < 3 mins Time < 3 mins 3 mins Time < 3 mins  3 Hours MEK DRs <3 MEK DRs < 3 MEK DRs < 3 MEK DRs < 3 MEK DRs < 3 MEK DRs < 3  27 HoursMEK DRs 2 MEK DRs 2 MEK DRs 2 MEK DRs 2 MEK DRs 10 MEK DRs 2 124 HoursMEK DRs 6 MEK DRs 6 MEK DRs 6 MEK DRs 6 MEK DRs 10 MEK DRs 7 264 HoursMEK DRs 20 MEK DRs 30 MEK DRs 30 MEK DRs 35 MEK DRs 30 MEK DRs 30 480Hours MEK DRs 25 MEK DRs 25 MEK DRs 25 MEK DRs 30 MEK DRs 30 MEK DRs 30

As shown in Table 2, the resin containing the MEKO anti-skinning agentshowed the fastest dry-through rate due to the high volatility of MEKObut yielded the poorest anti-skinning performance as seen in Example 1.The samples containing DEHA with an alkyl alkanolamine showed similardry-through properties to the sample containing DEHA with DEF.

Example 2 shows that the combination of diethylhydroxylamine with analkyl alkanolamine showed increased resistance to skinning, withoutcompromising dry-through performance in comparison to the prior art MEKOand DEHA with DEF.

Example 3

This example shows the dry-through performance of the short-oil resinused in Example 1 with eqimolar amounts of antiskinning agents usingalkyl amines, based on 750 ppm DEHA (0.084 mmol DEHA/10 gram of resin).The same procedure used in Example 2 was used in Example 3. TABLE 3 MEKO(0.337 mmol) Diethylhydroxylamine (0.337 mmol × 25% = (0.065 mmol) +Diethyl DEHA (0.068 DEHA (0.068 DEHA (0.069 0.084 mmol formamide mmol) +DiPA DEHA (0.068 mmol) + DBA mmol) + TBA mmol) + TEA Drying Time activeMEKO) (0.016 mmol) (0.017 mmol) (0.017 mmol) (0.017 mmol) (0.017 mmol)Tack Free Tack Free Tack Free Time < 3 mins Tack Free Tack Free Time < 3mins Tack Free Tack Free Time < 3 mins Time < 3 mins Time < 3 mins Time< 3 mins Time < 3 mins  3 Hours MEK DRs < 3 MEK DRs < 3 MEK DRs < 3 MEKDRs < 3 MEK DRs < 3 MEK DRs < 3  27 Hours MEK DRs 10 MEK DRs 2 MEK DRs 2MEK DRs 2 MEK DRs 2 MEK DRs 2 124 Hours MEK DRs 10 MEK DRs 7 MEK DRs 8MEK DRs 10 MEK DRs 11 MEK DRs 10 264 Hours MEK DRs 30 MEK DRs 30 MEK DRs25 MEK DRs 30 MEK DRs 25 MEK DRs 30 480 Hours MEK DRs 30 MEK DRs 30 MEKDRs 25 MEK DRs 30 MEK DRs 30 MEK DRs 30

The resin containing the MEKO anti-skinning agent showed the fastestdry-through rate due to the high volatility of MEKO but yielded thepoorest anti-skinning performance as seen in Example 1. The samplescontaining DEHA with an alkyl amine showed better dry-throughperformance after 124 hours than the sample containing DEHA with DEF.The samples containing DEHA with an alkyl amine showed similar resultsafter 264 and 480 hours to the Borcher 0241 (DEHA with DEF availablefrom Borcher GmbH Ltd.) but enhanced anti-skinning performance as seenin Example 1.

Example 3 shows that the combination of diethylhydroxylamine with analkyl amine showed increased resistance to skinning, withoutcompromising dry-through performance in comparison to the prior art MEKOand DEHA with DEF.

Example 4

This example shows the performance of DEHA-alkyl alkanolamineformulations containing no additional volatile organic compounds such asDEF in a medium oil resin. A common medium oil resin, Beckosol 11081(available form Reichhold Chemicals, Inc.) containing 50% solids wasused to compare MEKO to combinations of DEHA and alkyl alkanolamines.Cobalt octoate was added to the resin so the final cobalt ionconcentration was 0.2%. To the resin-cobalt mixture was added MEKO, orDEHA with an alkyl alkanolamine. Ten-gram samples were prepared on aneqimolar basis using 750 ppm (e.g., 750 mg/l; 0.0084 mol DEHA/l) ofdiethylhydroxylamine hydroxide (DEHA). TABLE 4 DiethylhydroxylamineDiethylhydroxylamine Diethylhydroxylamine MEKO MEKO (0.065 mmol) +Diethyl (0.068 mmol) + (0.069 mmol) + (0.055 mmol (0.114 mmol formamideDiisoproplyaminoethanol Ethylaminoethanol active) active) (0.016 mmol)(0.018 mmol) (0.018 mmol) 2 Days 7 Days 32 Days 37 Days 37 Days

The MEKO samples showed poor resistance to skinning even at 0.114 mmol.The sample containing diethylhydroxylamine with diethyl formamide showedbetter skinning performance than the MEKO samples. The samplescontaining diethylhydroxylamine with alkyl alkanaolamines, DiPAE or EAEshowed the best overall skinning performance. The skinning performanceof the samples containing DEHA with an alkyl alkanolamine performedbetter than that containing DEHA with DEF yet no additional co-solventswere necessary in the DEHA-alkyl alkanolamine samples.

Example 5

This example shows the dry-through performance of the medium oil resinused in Example 4 with eqimolar amounts of antiskinning agents, based on750 ppm DEHA (˜0.085 mmol DEHA/10 gram of resin). The cobaltconcentration for the dry-through performance study was decreased to0.1%. The resin with the cobalt drier and the antiskinning agents wereplaced onto substrate and a drawdown bar was used to apply a three milthick coating. The samples were placed in an exhaust hood with airflowing over the samples at about 100 feet per minute. The tack-freetime was determined by the absence of a fingerprint on the resin. TABLE5 MEKO (0.4487 mmol) (0.4487 mmol × 25% = 0.112 mmolDiethylhydroxylamine Drying active (0.085 mmol) + Diethyl DEHA DEHA(0.068 mmol) + DiPAE DEHA (0.068 mmol) + TBA Time MEKO) formamide (0.026mmol) (0.090 mmol) (0.017 mmol) (0.017 mmol) Tack- Tack Free Time > TackFree Time > 2 Hours Tack Free Tack Free Time > 2 Hours Tack Free Time >2 Hours Free 2 Hours Time > 2 Hours  3.5 MEK DRs 11 MEK DRs 8 MEK DRs 7MEK DRs 8 MEK DRs 7 Hours  30 MEK DRs 14 MEK DRs 11 MEK DRs 8 MEK DRs 9MEK DRs 9 Hours 146 MEK DRs 14 MEK DRs 12 MEK DRs 12 MEK DRs 12 MEK DRs12 Hours

The resin containing the MEKO anti-skinning agent showed the fastestdry-through rate due to the high volatility of MEKO but yielded thepoorest anti-skinning performance as seen in Example 1. After about 30hours, the samples containing DEHA with either an alkyl amine (TBA) oran alkyl alkanolamine (DiPAE) showed similar dry-through performance tothe DEHA sample containing the DEF but no additional VOC are present aswith the use of DEF.

Example 6

This example shows the dry-through performance of the medium oil resinused in Example 4 with eqimolar amounts of antiskinning agents based on750 ppm DEHA (˜0.085 mmol DEHA/10 gram of resin). However, the DEHAconcentration was lowered to 0.0515 mmol and the amine concentration wasincreased to 0.0340 mmol. The cobalt concentration for the dry-throughperformance study was 0.1%. The resin with the cobalt drier and theantiskinning agents were placed onto a substrate and a drawdown bar wasused to apply a three mil thick coating. The samples were placed in anexhaust hood with air flowing over the samples at about 100 feet perminute. The tack-free time was determined by the absence of afingerprint on the resin. TABLE 6 MEKO (0.4487 mmol) (0.4487 mmol × 25%= 0.112 mmol Diethylhydroxylamine Drying active (0.085 mmol) + DiethylDEHA DEHA (0.0515 mmol) + DiPAE DEHA (0.0515 mmol) + TBA Time MEKO)formamide (0.026 mmol) (0.090 mmol) (0.0342 mmol) (0.0342 mmol) Tack-Tack Free Time > Tack Free Time > 2 Hours Tack Free Tack Free Time > 2Hours Tack Free Time > 2 Hours Free 2 Hours Time > 2 Hours  3.5 MEK DRs11 MEK DRs 8 MEK DRs 7 MEK DRs 8 MEK DRs 10 Hours  30 MEK DRs 14 MEK DRs11 MEK DRs 8 MEK DRs 10 MEK DRs 11 Hours 146 MEK DRs 14 MEK DRs 12 MEKDRs 12 MEK DRs 14 MEK DRs 13 Hours

The resin containing the MEKO anti-skinning agent showed the fastestdry-through rate due to the high volatility of MEKO but yielded thepoorest anti-skinning performance as seen in Example 1. After about 30hours, the samples containing DEHA with either an alkyl amine (TBA) oran alkyl alkanolamine (DiPAE) showed similar dry-through performance tothe DEHA sample containing the DEF but no additional VOC are present aswith the use of DEF.

Examples 7

Additional testing of the antiskinning properties of antiskinning agentsalone and with co-promoters was undertaken. The test solutions, Athrough L as described below were prepared. Tung oil was used as thecuring medium. When cobaltous, Co(II), is added to tung oil it quicklycauses curing, loss of cis unsaturation in the oil producing a hardfilm. Addition of an anti-skin agent can slow the curing of tung oil.

Tung oil in combination with cobalt (Co) dryer was used as a resinmatrix in this example. The resin matrix was formed from a 150 gramsample of tung oil to which was added 0.1% by weight of Co(II) (Co 12available from OMG America, Westlake, Ohio). The cobalt was adequatelymixed into the tung oil.

Concentrated anti-skin agent and anti-skin agent/co-promoter solutionswere prepared as follows:

Solution A: Methyl ethyl ketoxime: 25% active solution in mineralspirits: added 1.40 grams of this 25% active solution into 8.60 grams ofmineral spirits.

Solution B: Hydroquinone (HQ): dissolved 1.402 grams HQ into 8.60 gramsinto mineral spirits.

Solution C: Methylhydroquinone (MeHQ): dissolved 1.401 grams MeHQ into8.60 grams of mineral spirits.

Solution D: Methyl ethyl ketoxime (MEKO)/Diisopropylaminoethanol (DiPAE)-MEKO, as a 25% active solution in mineral spirits: added 1.093 grams ofthis 25% active MEKO solution along with 0.307 grams DiPAE into 8.60grams of mineral spirits.

Solution E: Hydroquinone (HQ)/Diisopropylaminoethanol (DiPAE): dissolved0.7484 grams HQ and 0.6516 grams of DiPAE into 8.60 grams into mineralspirits.

Solution F: Methylhydroquinone (MeHQ)/Diisopropylaminoethanol (DiPAE):

dissolved 0.7900 grams MeHQ and 0.610 grams DiPAE into 8.60 grams ofmineral spirits.

Solution G: Methyl ethyl ketoxime: 25% active solution in mineralspirits: added 1.403 grams of this 25% active solution into 8.60 gramsof water.

Solution H: Hydroquinone (HQ): dissolved 1.406 grams HQ into 8.60 gramsinto water.

Solution I: Methylhydroquinone (MeHQ): dissolved 1.402 grams MeHQ gramsinto 8.60 grams of water.

Solution J: Methyl ethyl ketoxime (MEKO)/Diisopropylaminoethanol(DiPAE): 25% active solution MEKO in mineral spirits: added 1.093 gramsof this 25% active solution along with 0.307 grams DiPAE into 8.60 gramsof water.

Solution K: Hydroquinone (HQ)/Diisopropylaminoethanol (DiPAE): dissolved0.7484 grams HQ and 0.6516 grams of DiPAE into 8.60 grams into water.

Solution L: Methylhydroquinone (MeHQ)/Diisopropylaminoethanol (DiPAE):dissolved 0.7900 grams MeHQ and 0.610 grams DiPAE into 8.60 grams ofwater.

The above solutions were formulated into the following samples and theonset of skin formation evaluated.

Sample 1: No Antiskin Agent: A 10 gram sample was tung oil/Co drierplaced in a glass bottle. The bottle was placed in an exhaust hood withair flowing over the top of the glass bottle at the rate ofapproximately 100 ft³/minute.

Sample 2: To a 10 gram sample of tung oil/Co drier was added 0.2096grams of Solution A above (MEKO in mineral spirits). The solution wasmixed in a glass bottle and placed in an exhaust hood with air flowingover the top of the glass bottle at the rate of approximately 100ft³/minute.

Sample 3: To a 10 gram sample of tung oil/Co drier was added 0.0675grams of Solution B above (HQ in mineral spirits). The solution wasmixed in a glass bottle and placed in an exhaust hood with air flowingover the top of the glass bottle at the rate of approximately 100ft³/minute.

Sample 4: To a 10 gram sample of tung oil/Co drier was added 0.0759grams of Solution C above (MeHQ in mineral spirits). The solution wasmixed in a glass bottle and placed in an exhaust hood with air flowingover the top of the glass bottle at the rate of approximately 100ft³/minute.

Sample 5: To a 10 gram sample of tung oil/Co drier was added 0.1610grams of Solution D above (MEKO/DiPAE in mineral spirits). The solutionwas mixed in a glass bottle and placed in an exhaust hood with airflowing over the top of the glass bottle at the rate of approximately100 ft³/minute.

Sample 6: To a 10 gram sample of tung oil/Co drier was added 0.0759grams of Solution E above (HQ/DiPAE in mineral spirits). The solutionwas mixed in a glass bottle and placed in an exhaust hood with airflowing over the top of the glass bottle at the rate of approximately100 ft³/minute.

Sample 7: To a 10 gram sample of tung oil/Co drier was added 0.0812grams of Solution F above (MeHQ/DiPAE in mineral spirits). The solutionwas mixed in a glass bottle and placed in an exhaust hood with airflowing over the top of the glass bottle at the rate of approximately100 ft³/minute.

Sample 8: To a 10 gram sample of tung oil/Co drier was added 0.2091grams of Solution G above (MEKO in water). The solution was mixed in aglass bottle and placed in an exhaust hood with air flowing over the topof the glass bottle at the rate of approximately 100 ft³/minute.

Sample 9: To a 10 gram sample of tung oil/Co drier was added 0.0671grams of Solution H above (HQ in water). The solution was mixed in aglass bottle and placed in an exhaust hood with air flowing over the topof the glass bottle at the rate of approximately 100 ft³/minute.

Sample 10: To a 10 gram sample of tung oil/Co drier was added 0.0762grams of Solution I above (MeHQ in water). The solution was mixed in aglass bottle and placed in an exhaust hood with air flowing over the topof the glass bottle at the rate of approximately 100 ft³/minute.

Sample 11: To a 10 gram sample of tung oil/Co drier was added 0.1599grams of Solution J above (MEKO/DiPAE in water). The solution was mixedin a glass bottle and placed in an exhaust hood with air flowing overthe top of the glass bottle at the rate of approximately 100 ft³/minute.

Sample 12: To a 10 gram sample of tung oil/Co drier was added 0.0760grams of Solution K above (HQ/DiPAE in water). The solution was mixed ina glass bottle and placed in an exhaust hood with air flowing over thetop of the glass bottle at the rate of approximately 100 ft³/minute.

Sample 13: To another 10 gram sample of tung oil/Co drier was added0.0819 grams of Solution L above (MeHQ/DiPAE in water). The solution wasmixed in a glass bottle and placed in an exhaust hood with air flowingover the top of the glass bottle at the rate of approximately 100ft³/minute.

The results of the testing of samples A through L are summarized inTable 7. TABLE 7 Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6Sample 7 Day 1 Skinned No Skin No Skin No Skin No Skin No Skin No SkinDay 2 Skinned No Skin No Skin No Skin No Skin No Skin No Skin Day 4Skinned No Skin No Skin No Skin No Skin No Skin No Skin Day 5 SkinnedStart of No Skin No Skin No Skin No Skin No Skin Skin Day 6 SkinnedStart of No Skin No Skin No Skin No Skin No Skin Skin Day 7 SkinnedSkinned No Skin No Skin No Skin No Skin No Skin Day 8 Skinned SkinnedStart of No Skin No Skin No Skin No Skin Skin Day 9 Skinned SkinnedStart of Start of Start of No Skin No Skin Skin Skin Skin Day 10 SkinnedSkinned Skinned Start of Start of No Skin No Skin Skin Skin Day 11Skinned Skinned Skinned Skinned Skinned Start of Start of Skin Skin Day12 Skinned Skinned Skinned Skinned Skinned Skinned Skinned Sample 1Sample 8 Sample 9 Sample 10 Sample 11 Sample 12 Sample 13 Day 1 SkinnedNo Skin No Skin No Skin No Skin No Skin No Skin Day 2 Skinned No Skin NoSkin No Skin No Skin No Skin No Skin Day 4 Skinned Start of No Skin NoSkin No Skin No Skin No Skin Skin Day 5 Skinned Start of No Skin No SkinNo Skin No Skin No Skin Skin Day 6 Skinned Skinned No Skin No Skin NoSkin No Skin No Skin Day 7 Skinned Skinned No Skin No Skin No Skin NoSkin No Skin Day 8 Skinned Skinned No Skin No Skin No Skin No Skin NoSkin Day 9 Skinned Skinned No Skin No Skin No Skin No Skin No Skin Day10 Skinned Skinned Start of Skin Start of Skin No Skin No Skin No SkinDay 11 Skinned Skinned Start of Skin Start of Skin No Skin No Skin NoSkin Day 12 Skinned Skinned Skinned Skinned Start of No Skin No SkinSkin Day 13 Skinned Skinned Skinned Skinned Skinned Start of Start ofSkin Skin Day 14 Skinned Skinned Skinned Skinned Skinned Skinned SkinnedDay 15 Skinned Skinned Skinned Skinned Skinned Day 16 Skinned SkinnedSkinned Skinned Skinned Skinned SkinnedThe data in Table 7 shows the efficacy of the combination of the presentinvention at controlling skin formation without adversely impacting drythrough time. The data shows an oxygen scavenger and alkyl amine and/oralkyl alkanolamine can be dissolved in mineral spirits or water thenadded to the alkyd during manufacture of the resin to provide a resinwith acceptable dry through ad controlled skin formation.

While the present invention has been described with respect toparticular embodiments thereof, it is apparent that numerous other formsand modifications of this invention will be obvious to those skilled inthe art. The appended claims and this invention generally should beconstrued to cover all such obvious forms and modifications which arewithin the true spirit and scope of the present invention.

1. A coating material, paint or finish which contains an oxidativelydrying film former and, as an antiskinning agent, a combinationcomprising a) an organic or inorganic oxygen scavenger of, with b) analkyl amine of formula (II)

where R³, R⁴ and R⁵ may be mutually independently hydrogen but all threecan not be hydrogen, a linear or branched, saturated or unsaturatedC₁-C₂₀ aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, or a C₆-C₁₂ aryl molecule or radical, a C₇-C₁₄araliphatic molecule or radical or a C₅-C₇ cycloaliphatic molecule orradical, and/or c) an alkyl alkanol amine of formula (III)

where R⁶ and R⁸ may be mutually independently hydrogen but both can notbe hydrogen, a linear or branched, saturated or unsaturated C₁-C₂₀aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, a C₆-C₁₂ aryl molecule or radical, a C₇-C₁₄ araliphaticmolecule or radical or a C₅-C₇ cycloaliphatic molecule or radical and R⁷may be a linear or branched, saturated or unsaturated C₁-C₂₀ aliphaticmolecule or radical, which can optionally be mono- or polysubstituted, aC₆-C₁₂ aryl molecule or radical, a C₇-C₁₄ araliphatic molecule orradical or a C₅-C₇ cycloaliphatic molecule or radical.
 2. The coatingmaterial, paint or finish of claim 1 wherein said organic or inorganicoxygen scavenger is a hydroxylamine of the general formula:

where R¹ and R² mutually independently hydrogen, a linear or branched,saturated or unsaturated C₁-C₂₀ aliphatic molecule or radical, which canoptionally be mono- or polysubstituted, or a C₆-C₁₂ aryl molecule orradical, a C₇-C₁₄ araliphatic radical or a C₅-C₇ cycloaliphatic.
 3. Thecoating material, paint or finish of claim 2 wherein the hydroxylamineis selected from hydroxylamine, mono-methylhydroxylamine,dimethylhydroxylamine, methyl ethylhydroxylamine,monoethylhydroxylamine, diethylhydroxylamine, dibutylhydroxylamine,dibenzylhydroxylamine, mono-isopropylhydroxylamine and mixtures thereof.4. The coating material, paint or finish of claim 1 wherein the organicor inorganic oxygen scavenger is selected from hydroquinone, substitutedhydroquinones, semi-hydroquinone, catechol, substituted catechols,erythorbic acid, carbohydrazides, methyl ethyl ketoxime and sulfites. 5.The coating material, paint or finish of claim 1 wherein the alkyl amineis selected from: monoethyl amine, diethyl amine, triethyl amine,monoisopropyl amine, diisopropyl amine, monobutyl amine, dibutylamine,tributyl amine, monoamyl amine, dimethyl ethyl amine, dimethyl isopropylamine, ethyl diisopropyl amine, sec-butyl amine,tetramethylpropylenediamine, diethylaminopropylamine,3-methoxypropylamine, dimethylaminopropylaminopropylamine and3-isopropoxypropylamine and mixtures thereof.
 6. The coating material,paint or finish of claim 1 wherein the alkyl alkanolamine is selectedfrom: methylaminoethanol, dimethylaminoethanol, methydiethanolamine,ethylaminoethanol, diethylaminoethanol, dimethylamino-2-propanol,isopropylaminoethanol, disiopropylaminoethanol, butylaminoethanol,dibutylaminoethanol, butyldiethanolamine, tert-butylaminoethanol andmixtures thereof.
 7. The coating material, paint or finish of claim 1,which contains the said combination in an amount of from 0.001 to 2% byweight, based on the total surface coating.
 8. The coating material,paint or finish of claim 1, which contains an alkyd resin as theoxidatively drying film former.
 9. A process for the production of acoating material, paint or finish containing an oxidatively drying filmformer comprising incorporating into the coating material, paint orfinish, an antiskinning combination comprising a) an organic orinorganic oxygen scavenger, with b) an alkyl amine of formula (II)

where R³, R⁴ and R⁵ may be mutually independently hydrogen but all threecan not be hydrogen, a linear or branched, saturated or unsaturatedC₁-C₂₀ aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, or a C₆-C₁₂ aryl molecule or radical, a C₇-C₁₄araliphatic molecule or radical or a C₅-C₇ cycloaliphatic molecule orradical, and/or c) an alkyl alkanolamine of formula (III)

where R⁶ and R⁸ may be mutually independently hydrogen but both can notbe hydrogen, a linear or branched, saturated or unsaturated C₁-C₂₀aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, a C₆-C₁₂ aryl molecule or radical, a C₇-C₁₄ araliphaticradical or a C₅-C₇ cycloaliphatic molecule or radical and R⁷ may be alinear or branched, saturated or unsaturated C₁-C₂₀ aliphatic moleculeor radical, which can optionally be mono- or polysubstituted, a C₆-C₁₂aryl molecule or radical, a C₇-C₁₄ araliphatic molecule or radical or aC₅-C₇ cycloaliphatic molecule or radical.
 10. The process of claim 9wherein the said organic or inorganic oxygen scavenger is ahydroxylamine of the general formula I,

where R¹ and R² mutually independently hydrogen, a linear or branched,saturated or unsaturated C₁-C₂₀ aliphatic molecule or radical, which canoptionally be mono- or polysubstituted, or a C₆-C₁₂ aryl molecule orradical, a C₇-C₁₄ araliphatic molecule or radical or a C₅-C₇cycloaliphatic molecule or radical.
 11. The process of claim 9 whereinsaid hydroxylamine is selected from hydroxylamine,mono-methylhydroxylamine, dimethylhydroxylamine, methylethylhydroxylamine, monoethylhydroxylamine, diethylhydroxylamine,dibutylhydroxylamine, dibenzylhydroxylamine, mono-isopropylhydroxylamineand mixtures thereof.
 12. The process of claim 9 wherein the organic orinorganic oxygen scavenger is selected from hydroquinone, substitutedhydroquinones, semi-hydroquinone, catechol, substituted catechols,erythorbic acid, carbohydrazides, methyl ethyl ketoxime and sulfites.13. The process of claim 9 wherein the alkyl amine is selected from:monoethyl amine, diethyl amine, triethyl amine, monoisopropyl amine,diisopropyl amine, monobutyl amine, dibutylamine, tributyl amine,monoamyl amine, dimethyl ethyl amine, dimethyl isopropyl amine, ethyldiisopropyl amine, sec-butyl amine, tetramethylpropylenediamine,diethylaminopropylamine, 3-methoxypropylamine,dimethylaminopropylaminopropylamine and 3-isopropoxypropylamine andmixtures thereof.
 14. The process of claim 9 wherein the alkylalkanolamine is selected from: methylaminoethanol, dimethylaminoethanol,methydiethanolamine, ethylaminoethanol, diethylaminoethanol,dimethylamino-2-propanol, isopropylaminoethanol,disiopropylaminoethanol, butylaminoethanol, dibutylaminoethanol,butyldiethanolamine, tert-butylaminoethanol and mixtures thereof. 15.The process of claim 9, wherein said coating material, paint or finishcontaining an oxidatively drying film former contains said combinationin an amount of from 0.001 to 2% by weight, based on the total surfacecoating.
 16. The process of claim 9, wherein said coating material,paint or finish containing an oxidatively drying film former contains analkyd resin as the oxidatively drying film former.
 17. An article coatedwith a coating material, paint or finish containing an oxidativelydrying film former, wherein an antiskinning combination comprising a) anorganic or inorganic oxygen scavenger; with b) an alkyl amine of formula(II)

where R³, R⁴ and R⁵ may be mutually independently hydrogen but all threecan not be hydrogen, a linear or branched, saturated or unsaturatedC₁-C₂₀ aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, or a C₆-C₁₂ aryl molecule or radical, a C₇-C₁₄araliphatic molecule or radical or a C₅-C₇ cycloaliphatic molecule orradical, and/or c) an alkyl alkanolamine of formula (III)

where R⁶ and R⁸ may be mutually independently hydrogen but both can notbe hydrogen, a linear or branched, saturated or unsaturated C₁-C₂₀aliphatic molecule or radical, which can optionally be mono- orpolysubstituted, a C₆-C₁₂ aryl molecule or radical, a C₇-C₁₄ araliphaticmolecule or radical or a C₅-C₇ cycloaliphatic molecule or radical and R⁷may be a linear or branched, saturated or unsaturated C₁-C₂₀ aliphaticmolecule or radical, which can optionally be mono- or polysubstituted, aC₆-C₁₂ aryl radical, a C₇-C₁₄ araliphatic molecule or radical or a C₅-C₇cycloaliphatic molecule or radical is incorporated into the coatingmaterial, paint or finish.
 18. The article of claim 17 wherein saidorganic or inorganic oxygen scavenger is a hydroxylamine of the generalformula:

where R¹ and R² mutually independently hydrogen, a linear or branched,saturated or unsaturated C₁-C₂₀ aliphatic molecule or radical, which canoptionally be mono- or polysubstituted, or a C₆-C₁₂ aryl molecule orradical, a C₇-C₁₄ araliphatic molecule or radical or a C₅-C₇cycloaliphatic molecule or radical.
 19. The article of claim 18 whereinsaid hydroxylamine is selected from hydroxylamine,mono-methylhydroxylamine, dimethylhydroxylamine, methylethylhydroxylamine, monoethylhydroxylamine, diethylhydroxylamine,dibutylhydroxylamine, dibenzylhydroxylamine, mono-isopropylhydroxylamineand mixtures thereof.
 20. The article of claim 17 wherein the organic orinorganic oxygen scavenger is selected from hydroquinone, substitutedhydroquinones, semi-hydroquinone, catechol, substituted catechols,erythorbic acid, carbohydrazides, methyl ethyl ketoxime and sulfites.21. The article of claim 17 wherein the alkyl amine is selected from:monoethyl amine, diethyl amine, triethyl amine, monoisopropyl amine,diisopropyl amine, monobutyl amine, dibutylamine, tributyl amine,monoamyl amine, dimethyl ethyl amine, dimethyl isopropyl amine, ethyldiisopropyl amine, sec-butyl amine, tetramethylpropylenediamine,diethylaminopropylamine, 3-methoxypropylamine,dimethylaminopropylaminopropylamine and 3-isopropoxypropylamine andmixtures thereof.
 22. The article of claim 17 wherein the alkylalkanolamine is selected from: methylaminoethanol, dimethylaminoethanol,methydiethanolamine, ethylaminoethanol, diethylaminoethanol,dimethylamino-2-propanol, isopropylaminoethanol,disiopropylaminoethanol, butylaminoethanol, dibutylaminoethanol,butyldiethanolamine, tert-butylaminoethanol and mixtures thereof. 23.The article of claim 17, wherein said coating material, paint or finishcontaining an oxidatively drying film former contains said combinationin an amount of from 0.001 to 2% by weight, based on the total surfacecoating.
 24. The article of claim 17, wherein said coating material,paint or finish containing an oxidatively drying film former contains analkyd resin as the oxidatively drying film former.